We work together http://www.rudolph-valentino.com/write-a-essays/ writing a reference letter for a student  There has been no claim of responsibility for the recent wave of attacks, but Sunni extremists, including al-Qaida's Iraq branch, are believed to be responsible for much of the killing. They frequently target Shiites, security forces and civil servants in an effort to undermine the Shiite-led government in Baghdad.